Trap design can influence fly attraction and capture. In this study, traps of 2 different housing designs were fitted with black light (ultraviolet) bulbs or black light blue bulbs, and black glue boards, either with or without the addition of house fly pheromone. Traps were placed on a lab bench ca. 1 m above the floor, both facing the same direction, separated by several meters and shining into the room. In a factorial design, trap housings were fitted with both bulb and glue board types in all combinations. When housing combinations were in place and lights were illuminated, 50 mixed-sex 3- to 5-day-old house flies were released into the room. Captured flies were counted 1, 4, and 24 hours after release. Housing combinations were replicated 4 times. Effects of trap housing and bulb type were striking and demonstrate the importance of each. Because these tests were performed in a laboratory, a field test using the same design must be completed to support or refute the findings.